Transmission assembly featuring one-way needle bearings for engine- and human-powered vehicles

ABSTRACT

A transmission assembly for a human- and/or motor-powered vehicle, including a hollow transfer shaft, first and second inner one-way needle bearings, the first inner one-way needle bearing disposed within a first hollow end of the transfer shaft, and the second inner one-way needle bearing disposed within a second hollow end of the transfer shaft; and a first and a second outer two-way needle bearings, each having an inner diameter and an outer diameter, the first outer two-way needle bearing disposed about the outer diameter of the transfer shaft near the first hollow end of the transfer shaft, and the second outer two-way needle bearing disposed about the outer diameter of the transfer shaft near the second end of the transfer shaft, such that the inner diameter of each of the first and second outer two-way needle bearings contacts the outer diameter of the transfer shaft.

FIELD OF THE INVENTION

The device disclosed and claimed herein is directed to a transmissionassembly for vehicles that can be powered by both an engine and by humanpower, such as a motorized bicycle.

BACKGROUND

Motorized bicycles are known in the art. See, for example, U.S. Pat. No.4,397,369, to Read; U.S. Pat. No. 5,361,863, to Goodwin; U.S. Pat. No.7,284,463, to Rizzetto; U.S. Pat. No. 7,770,682, to Spanski; U.S. Pat.No. 8,051,937, to Pesenti; and Published Pat. Appl. US 2005/0039963, toForderhase. A significant drawback to these designs is that they areheavy and overly complicated. Because of their weight, they are notpractically operable by human power alone. Thus, they are not bicyclesin the truest sense of being operable over any appreciably long distancevia the leg-power of the rider. They are more akin to motorcycles anddesigned to be powered exclusively (or very nearly so) by the affixedengine. Because the transmission assembly that links the engine to thegear-train that drives the wheels is complicated, the prior designs aredifficult to manufacture and cannot be easily implemented into existingassembly lines for making conventional bicycles or other human-poweredvehicles (tricycles, 4-wheelers, etc.). Thus, there remains a long-feltand unmet need for a lightweight transmission of a design that enables avehicle to be powered with equal facility either by the human rider orby an engine.

SUMMARY OF THE INVENTION

Disclosed is a transmission assembly comprising a hollow transfer shaft20 having an inner diameter, an outer diameter, and defining a firsthollow end, and a second hollow end; a first (22) and a second (22′)inner one-way needle bearings each having an inner diameter and an outerdiameter, the first inner one-way needle bearing disposed within thefirst hollow end of the transfer shaft 20, and the second inner one-wayneedle bearing disposed within the second hollow end of the transfershaft 20, such that the outer diameter of each of the first (22) andsecond (22′) inner one-way needle bearings contacts the respective innerdiameter 25, 25′ of the transfer shaft; and a first and a second outertwo-way needle bearings, 24 and 24′, each having an inner diameter andan outer diameter, the first outer two-way needle bearing disposed aboutthe outer diameter of the transfer shaft near the first hollow end ofthe transfer shaft, and the second outer two-way needle bearing disposedabout the outer diameter of the transfer shaft near the second end ofthe transfer shaft, such that the inner diameter of each of the firstand second outer two-way needle bearings contacts the outer diameter ofthe transfer shaft.

In one version of the transmission assembly, wherein the inner diameterof each of the first and second inner one-way needle bearings 22 and 22′respectively is dimensioned and configured to contact an outer surfaceof a pedal input shaft 14 of a human-powered vehicle. The pedal inputshaft 14 may be the transfer shaft of a bicycle. The outer diameter ofeach of the first and second outer two-way needle bearings 24 and 24′may be dimensioned and configured to contact an inner diameter of abottom bracket shell 15 of a human-powered vehicle, such as a bicycle asshown in FIG. 4.

The transmission assembly may further comprise a first side thrustbearing 23 disposed around the outer diameter of the transfer shaft atthe first hollow end of the transfer shaft and in contact with the firstouter two-way needle bearing 24; and a second side thrust bearing 23′disposed around the outer diameter of the transfer shaft at the secondhollow end of the transfer shaft and in contact with the second outertwo-way needle bearing 24′.

In another version, the transmission assembly comprises a pedal inputshaft 14 having an outer diameter, a first threaded end 13, and a secondthreaded end 13′, wherein the pedal input shaft 14 is disposed withinthe hollow transfer shaft, and wherein the outer diameter of the pedalinput shaft 14 contacts the inner diameter of each of the first andsecond inner, one-way needle bearings, 22 and 22′.

The transmission assembly may comprise a first drive plate 34 attachednear the first end of the transfer shaft 20 (near the first threaded end13) and a second drive plate 32 attached near the second end of thetransfer shaft 20 (near the second threaded end 13′). The threaded ends13 and 13′ are internally threaded bolt apertures used to attach thepedal crank arms tightly onto the flats of the pedal input shaft 14. Thetransmission assembly may further comprise a motor sprocket 36 attachedto the first drive plate 34. The transmission assembly may furthercomprise at least one chain ring 16 attached to the second drive plate32.

In yet another version of the transmission assembly, it may furtherinclude a first side thrust bearing 28 disposed around and in contactwith the outer diameter of the pedal input shaft 14 at a point closer tothe first end 13 of the transfer shaft than the first drive plate 34;and a second side thrust bearing 28′ disposed around and in contact withthe outer diameter of the pedal input shaft 14 at a point closer to thesecond end 13′ of the transfer shaft than the second drive plate 32,wherein the first and second side thrust bearings, 28 and 28′ are biasedtoward one another.

In yet another version, the transmission assembly comprises a hollowtransfer shaft 20 having an inner diameter, an outer diameter, anddefining a first hollow end, and a second hollow end; a first 22 and asecond 22′ inner one-way needle bearings, each having an inner diameterand an outer diameter, the first inner one-way needle bearing 22disposed within the first hollow end 25 of the transfer shaft, and thesecond inner one-way needle bearing 22′ disposed within the secondhollow end 25′ of the transfer shaft, such that the outer diameter ofeach of the first and second inner one-way needle bearings contacts theinner diameter of the transfer shaft; a first 24 and a second 24′ outertwo-way needle bearings, each having an inner diameter and an outerdiameter, the first outer two-way needle bearing 24 disposed about theouter diameter of the transfer shaft near the first hollow end of thetransfer shaft, and the second outer two-way needle bearing 24′ disposedabout the outer diameter of the transfer shaft near the second end ofthe transfer shaft, such that the inner diameter of each of the firstand second outer two-way needle bearings contacts the outer diameter ofthe transfer shaft; and a pedal input shaft 14 having an outer diameter,a first internally threaded end 13, and a second internally threaded end13′, wherein the pedal input shaft 14 is disposed within the hollowtransfer shaft 20, and wherein the outer diameter of the pedal inputshaft 14 contacts the inner diameter of each of the first and secondinner, one-way needle bearings, 22 and 22′, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevation, cross-sectional view of a transmissionassembly as disclosed and claimed herein.

FIG. 2 is an isolated, front elevation, cross-sectional, exploded viewof the bottom bracket shell 15 of a bicycle, with transfer shaft 20,inner one-way needle bearings 22, and outer two-way needle bearings 24,as shown in FIG. 1.

FIG. 3 is an isolated, front elevation, cross-sectional, exploded viewof drive plates 32 and 34 and motor sprocket 36 as shown in FIG. 1.

FIG. 4 depicts a bicycle having a motor attached thereto and linked tothe subject transmission assembly via a chain that attaches to motorsprocket 36 as shown in FIG. 1.

DETAILED DESCRIPTION

The same reference numerals are used throughout the four drawings.

Depicted in FIG. 1 is the subject transmission assembly in the contextof a conventional bicycle transmission designed to be powered by a humanrider. Thus, depicted in FIG. 1 are conventional pedals 10, crank arms12, and a pedal input shaft 14 passing through a bicycle bottom bracketshell 15. As shown in FIG. 1, the pedal input shaft 14 passes throughthe bottom bracket shell 15 and connects the end of each the crank arm12 that is opposite to its respective pedal 10. The pedal input shaft 14has first hollow end 13 and a second hollow end 13′ at either end (seeFIG. 2) to allow the crank arms 12 to be reversibly attached to thepedal input shaft 14 via bolts (not shown). Disposed about the pedalinput shaft 14 are conventional chain rings 16 (three are shown; theremay be more or less than three) and a chain guard 18.

Referring simultaneously to FIGS. 1 and 2, in the present transmission,the convention bottom bracket (not shown) is replaced with atransmission assembly that enables the vehicle (in the case of FIG. 4,which is exemplary, a bicycle) to be powered by the human rider, by anon-board engine or other power source (depicted in FIG. 4), or by both(the rider assisted by the engine). The on-board motor, engine, primemover, etc. depicted in FIG. 4 is conventional and will not be describedin any detail herein. Suitable engines of many different designs areavailable commercially. Any such engine or prime mover, of anyconfiguration (single- or multiple piston; straight-, V-, opposedpistons, etc., Wankel-style rotary, etc.) or energy source (electrical,gasoline, diesel, solar, etc.) may be used. As shown in FIGS. 1 and 2, ahollow transfer shaft 20 having an inner and outer diameter ispositioned around the pedal input shaft 14, within the bottom bracketshell 15. The transfer shaft 20 includes an inner diameter flange 21that defines first and second outer regions or ends 25 and 25′ whoseinner diameter is larger than the inner diameter about the flange 21.First and second inner one-way needle bearings 22 and 22′ respectivelyfit sleeve-like into the outer regions 25 and 25′ defined at either endof the transfer shaft 20 and contact the pedal input shaft 14. The innerone-way needle bearings 22 and 22′ are “one way” in that they rotatefreely in only one direction. The inner one-way needle bearings 22 and22′ are oriented to allow the vehicle to be human-powered via the pedals10 and crank arms 12, and also for the pedals to “free wheel” when thevehicle is coasting or at any time when the transfer shaft 20 isrotating faster than the pedals 10 and crank arms 12 are being rotated.

A first and second outer two-way needle bearings 24 and 24′,respectively, are positioned about the outer diameter of the transfershaft 20. The outer two-way needle bearings 24 and 24′ are held in placewithin the bottom bracket shell 15 via corresponding first and secondside thrust bearings 23 and 23′. In the same fashion as the innerone-way needle bearings 22 and 22′, the outer two-way needle bearings 24and 24′ are “two way” in that they rotate freely in both directions. Theinner one-way needle bearings 22 and 22′ are oriented to allow thevehicle to be powered by the onboard motor depicted in FIG. 4, yetsimultaneously to permit the pedals 10 and crank arms 12 to “freewheel.” In this fashion, a rider can either pedal the vehicle inconventional fashion, or leave the pedals stationary and allow thevehicle to be powered by the onboard engine, or a combination of thetwo; that is, to allow the onboard engine to assist the rider inpedaling the vehicle.

Referring now to FIGS. 1, 2, and 3, power is supplied from the engine tothe vehicle via a motor sprocket 36, which in turn is connected to afirst drive plate 34 via a plurality of sprocket bolt holes or any othersuitable connectors (see FIG. 3). The first drive plate 34 defines aneccentric, keyed, or otherwise non-circular aperture 35 that engages oneend of the transfer shaft 20. At the other end of the transfer shaft,the conventional chain rings are attached to a second drive plate 32.The second drive plate 32 also defines an eccentric, keyed, or otherwisenon-circular aperture 35′ that engages the other end of the transfershaft 20.

The entire collection of parts positioned within the bottom bracketshell 15, as well as the chain guard 18, chain rings 16, drive plates 32and 34, and the motor sprocket 36 attached to drive plate 34 are held inplace with respect to the bottom bracket shell 15 via a paired set ofwashers 26 and 26′, outer side thrust bearings 28 and 28′, and bearinghousings 30 and 30′. (One set of washer 26, outer side thrust bearing28, and bearing housing 30 is shown in FIG. 2. Both sets are shown inFIG. 1.) These two sets (26, 28, 30 and 26′, 28′, and 30′) are biasedtoward one another along the axis of the pedal input shaft 14.

In this fashion, both the motor sprocket 36 and the conventional chainrings 16 are attached to the pedal input shaft 14 in such a fashion thatthe vehicle can be powered by the motor shown in FIG. 4, or by humanpower transferred to the pedal input shaft 14 via the pedals 10 andcrank arms 12. The inner one-way needle bearings 22 and 22′ and outertwo-way needle bearings 24 and 24′ are oriented in such a fashion thatthe transfer shaft 20 can be rotated via energy transferred from themotor via motor sprocket 36 and first drive plate 34 and/or via energytransferred by the rider via pedals 10, crank arms 12, chain rings 16,and second drive plate 32. In other words, the inner one-way needlebearings 22 and 22′ cooperate with the outer two-way needle bearings 24and 24′ to enable the pedal input shaft 14 and the crank arms 12 andpedals 10 to free wheel when the transfer shaft 20 rotates faster thanthe crank arms and pedals are rotating.

Specifically referring to FIG. 3, the figure depicts the first driveplate 34 and the second drive plate 32, both in isolation and inassociation with motor sprocket 36 in the case of first drive plate 34and in association with the chain rings 16 in the case of second driveplate 32. Exemplary dimensions are included in FIG. 3 for purposes ofillustration only.

In FIG. 4 is depicted a conventional bicycle having a motor or primemover attached thereto, along with a conventional transmission and aconnector to connect the motor to the motor sprocket 36. In thisfashion, the bicycle depicted in FIG. 4 can be powered by a human riderby pushing the pedals 10 or the bicycle can be powered via the motor orthe motor can be used to assist a rider in powering the bicycle.

In its preferred version, outer bearings 24 and 24′ are regular, two-wayneedle bearings. Bearings 24 and 24′ are press fit into a conventionbike frame bottom bracket shell. The hollow transfer shaft 20 passesthrough and is supported by the outer needle bearings 24 and 24′. Thehollow transfer shaft has flats machined on each end which mate with theapertures 35′ and 35 shown in drive plates 32 and 34, respectively. (SeeFIG. 3.) The drive plates 32 and 34 are attached to the ends of thehollow transfer shaft 20 via these apertures. The motor sprocket 36 isattached to the first drive plate 34, while the chain rings 16 of thebicycle are attached to the second drive plate 32. This entire assembly(transfer shaft 20, drive plates 32 and 34, motor sprocket 36, and chainrings 16) thus rotates both forward and backward upon outer needlebearings 24 and 24′.

Inner one-way needle bearings 22 and 22′ are pressed the respectiveinner diameter 25, 25′ of the transfer shaft 20. The pedal input shaft14 passes through the hollow center of the transfer shaft 20 and issupported by the inner one-way needle bearings 22 and 22′. The bearings22 and 22′ are arranged in such a fashion that when the user pedals thebicycle using the conventional pedals, the pedal input shaft 14 willlock into the one-way needle bearings 22 and 22′, thereby allowing theuser to pedal the bicycle in conventional fashion. If the user wants themotor to power the bicycle, the inner bearings 22 and 22′ allow thepedal input shaft 14 (and attached pedals) to freewheel. This allows theuser to rest his feet on the pedal while the motor powers the bicycle.The pedal crank arms 12 are attached to the pedal input shaft 14 inconventional fashion. The paired set of washers 26 and 26′, outer sidethrust bearings 28 and 28′, and bearing housings 30 and 30′ are all heldin place by the same bolts that affix the pedal crank arms 12 to thepedal input shaft 14. In this fashion, when the crank arms 12 arefastened to the pedal input shaft 14, the entire assembly is heldtightly (but rotatably) within the bottom bracket shell of aconventional bicycle.

What is claimed is:
 1. A transmission assembly comprising: a hollowtransfer shaft having an inner diameter, an outer diameter, and defininga first hollow end, and a second hollow end; a first and a second innerone-way needle bearings, each having an inner diameter and an outerdiameter, the first inner one-way needle bearing disposed within thefirst hollow end of the transfer shaft, and the second inner one-wayneedle bearing disposed within the second hollow end of the transfershaft, such that the outer diameter of each of the first and secondinner one-way needle bearings contacts the inner diameter of thetransfer shaft; and a first and a second outer two-way needle bearings,each having an inner diameter and an outer diameter, the first outertwo-way needle bearing disposed about the outer diameter of the transfershaft near the first hollow end of the transfer shaft, and the secondouter two-way needle bearing disposed about the outer diameter of thetransfer shaft near the second end of the transfer shaft, such that theinner diameter of each of the first and second outer two-way needlebearings contacts the outer diameter of the transfer shaft.
 2. Thetransmission assembly of claim 1, wherein the inner diameter of each ofthe first and second inner one-way needle bearings is dimensioned andconfigured to contact an outer surface of a pedal input shaft of ahuman-powered vehicle.
 3. The transmission assembly of claim 1, whereinthe inner diameter of each of the first and second inner one-way needlebearings is dimensioned and configured to contact an outer surface of apedal input shaft of a bicycle.
 4. The transmission assembly of claim 1,wherein the outer diameter of each of the first and second outer two-wayneedle bearings is dimensioned and configured to contact an innerdiameter of a bottom bracket shell of a human-powered vehicle.
 5. Thetransmission assembly of claim 1, wherein the outer diameter of each ofthe first and second outer two-way needle bearings is dimensioned andconfigured to contact an inner diameter of a bottom bracket shell of abicycle.
 6. A transmission assembly comprising: a hollow transfer shafthaving an inner diameter, an outer diameter, and defining a first hollowend, and a second hollow end; a first and a second inner one-way needlebearings, each having an inner diameter and an outer diameter, the firstinner one-way needle bearing disposed within the first hollow end of thetransfer shaft, and the second inner one-way needle bearing disposedwithin the second hollow end of the transfer shaft, such that the outerdiameter of each of the first and second inner one-way needle bearingscontacts the inner diameter of the transfer shaft; and a first and asecond outer two-way needle bearings, each having an inner diameter andan outer diameter, the first outer two-way needle bearing disposed aboutthe outer diameter of the transfer shaft near the first hollow end ofthe transfer shaft, and the second outer two-way needle bearing disposedabout the outer diameter of the transfer shaft near the second end ofthe transfer shaft, such that the inner diameter of each of the firstand second outer two-way needle bearings contacts the outer diameter ofthe transfer shaft; and further comprising a first side thrust bearingdisposed around the outer diameter of the transfer shaft at the firsthollow end of the transfer shaft and in contact with the first outertwo-way needle bearing; and a second side thrust bearing disposed aroundthe outer diameter of the transfer shaft at the second hollow end of thetransfer shaft and in contact with the second outer two-way needlebearing; wherein the outer diameter of each of the first and secondouter two-way needle bearings is dimensioned and configured to contactan inner diameter of a bottom bracket shell of a bicycle.
 7. Thetransmission assembly of claim 1, further comprising a pedal input shafthaving an outer diameter, a first end, and a second end, wherein thepedal input shaft is disposed within the hollow transfer shaft, andwherein the outer diameter of the pedal input shaft contacts the innerdiameter of each of the first and second inner, one-way needle bearings.8. The transmission assembly of claim 7, further comprising a firstdrive plate attached near the first end of the transfer shaft and asecond drive plate attached near the second end of the transfer shaft.9. The transmission assembly of claim 8, further comprising a motorsprocket attached to the first drive plate.
 10. The transmissionassembly of claim 9, further comprising at least one chain ring attachedto the second drive plate.
 11. A transmission assembly comprising: ahollow transfer shaft having an inner diameter, an outer diameter, anddefining a first hollow end, and a second hollow end; a first and asecond inner one-way needle bearings, each having an inner diameter andan outer diameter, the first inner one-way needle bearing disposedwithin the first hollow end of the transfer shaft, and the second innerone-way needle bearing disposed within the second hollow end of thetransfer shaft, such that the outer diameter of each of the first andsecond inner one-way needle bearings contacts the inner diameter of thetransfer shaft; and a first and a second outer two-way needle bearings,each having an inner diameter and an outer diameter, the first outertwo-way needle bearing disposed about the outer diameter of the transfershaft near the first hollow end of the transfer shaft, and the secondouter two-way needle bearing disposed about the outer diameter of thetransfer shaft near the second end of the transfer shaft, such that theinner diameter of each of the first and second outer two-way needlebearings contacts the outer diameter of the transfer shaft; a pedalinput shaft having an outer diameter, a first end, and a second end,wherein the pedal input shaft is disposed within the hollow transfershaft, and wherein the outer diameter of the pedal input shaft contactsthe inner diameter of each of the first and second inner, one-way needlebearings; a first drive plate attached near the first end of thetransfer shaft and a second drive plate attached near the second end ofthe transfer shaft; a motor sprocket attached to the first drive plate;and further comprising a first side thrust bearing disposed around andin contact with the outer diameter of the transfer shaft at a pointcloser to the first end of the transfer shaft than the first driveplate; and a second side thrust bearing disposed around and in contactwith the outer diameter of the transfer shaft at a point closer to thesecond end of the transfer shaft than the second drive plate, whereinthe first and second side thrust bearings are biased toward one another.12. A transmission assembly comprising: a hollow transfer shaft havingan inner diameter, an outer diameter, and defining a first hollow end,and a second hollow end; a first and a second inner one-way needlebearings, each having an inner diameter and an outer diameter, the firstinner one-way needle bearing disposed within the first hollow end of thetransfer shaft, and the second inner one-way needle bearing disposedwithin the second hollow end of the transfer shaft, such that the outerdiameter of each of the first and second inner one-way needle bearingscontacts the inner diameter of the transfer shaft; a first and a secondouter two-way needle bearings, each having an inner diameter and anouter diameter, the first outer two-way needle bearing disposed aboutthe outer diameter of the transfer shaft near the first hollow end ofthe transfer shaft, and the second outer two-way needle bearing disposedabout the outer diameter of the transfer shaft near the second end ofthe transfer shaft, such that the inner diameter of each of the firstand second outer two-way needle bearings contacts the outer diameter ofthe transfer shaft; and a pedal input shaft having an outer diameter, afirst end, and a second end, wherein the pedal input shaft is disposedwithin the hollow transfer shaft, and wherein the outer diameter of thepedal input shaft contacts the inner diameter of each of the first andsecond inner, one-way needle bearings.
 13. The transmission assembly ofclaim 12, wherein the outer diameter of each of the first and secondouter two-way needle bearings is dimensioned and configured to contactan inner diameter of a bottom bracket shell of a human-powered vehicle.14. A transmission assembly comprising: a hollow transfer shaft havingan inner diameter, an outer diameter, and defining a first hollow end,and a second hollow end; a first and a second inner one-way needlebearings, each having an inner diameter and an outer diameter, the firstinner one-way needle bearing disposed within the first hollow end of thetransfer shaft, and the second inner one-way needle bearing disposedwithin the second hollow end of the transfer shaft, such that the outerdiameter of each of the first and second inner one-way needle bearingscontacts the inner diameter of the transfer shaft; a first and a secondouter two-way needle bearings, each having an inner diameter and anouter diameter, the first outer two-way needle bearing disposed aboutthe outer diameter of the transfer shaft near the first hollow end ofthe transfer shaft, and the second outer two-way needle bearing disposedabout the outer diameter of the transfer shaft near the second end ofthe transfer shaft, such that the inner diameter of each of the firstand second outer two-way needle bearings contacts the outer diameter ofthe transfer shaft; and a pedal input shaft having an outer diameter, afirst end, and a second end, wherein the pedal input shaft is disposedwithin the hollow transfer shaft, and wherein the outer diameter of thepedal input shaft contacts the inner diameter of each of the first andsecond inner, one-way needle bearings; and further comprising a firstside thrust bearing disposed around the outer diameter of the transfershaft at the first hollow end of the transfer shaft and in contact withthe first outer two-way needle bearing; and a second side thrust bearingdisposed around the outer diameter of the transfer shaft at the secondhollow end of the transfer shaft and in contact with the second outertwo-way needle bearing.
 15. The transmission assembly of claim 14,further comprising a first drive plate attached near the first end ofthe transfer shaft and a second drive plate attached near the second endof the transfer shaft.
 16. The transmission assembly of claim 15,further comprising a motor sprocket attached to the first drive plate.17. The transmission assembly of claim 16, further comprising at leastone chain ring attached to the second drive plate.
 18. The transmissionassembly of claim 17, further comprising a first side thrust bearingdisposed around and in contact with the outer diameter of the transfershaft at a point closer to the first end of the transfer shaft than thefirst drive plate; and a second side thrust bearing disposed around andin contact with the outer diameter of the transfer shaft at a pointcloser to the second end of the transfer shaft than the second driveplate, wherein the first and second side thrust bearings are biasedtoward one another.